1. Field of the Invention
This invention relates to a method for preparing silicon compounds of the formula
(R.sub.3 Si).sub.n NR'.sub.3-n or PA1 R.sub.2 si(NR'.sub.2).sub.2 or RSi(NR'.sub.2).sub.3 or PA1 Cyclic --R.sub.2 SiNR'--.sub.x PA1 (R.sub.3 Si).sub.n NR'.sub.3-n or PA1 R.sub.2 si(NR'.sub.2).sub.2 or RSi(NR'.sub.2).sub.3 or PA1 Cyclic --R.sub.2 SiNR'--.sub.x
Wherein R, R', n and x have the above-described meanings. More especially this invention relates to the preparation of such silicon-nitrogen compounds by contacting ammonia or an amine with a hydrogen silane of the formula R.sub.4-y SiH.sub.y.
2. Discussion of the Prior Art
Silazanes prepared by the process herein described have attained commercial importance owing to their use as synthesis adjuvants and protective group reagents in the synthesis of semisynthetic penicillins and cephalosproins, respectively, and other substances, as described, for instance, in U.S. Pat. No. 3,994,545.
The silicon-nitrogen compounds suitable for these purposes have hitherto been prepared by the reaction of chlorosilanes with amines, but several times the amount of amines is needed in order to bind the chloride that is formed as hydrochloride. This unavoidable production of amine hydrochlorides causes additional great disadvantages. The reaction must be performed in dilute solutions in order to keep the pulp stirrable and pumpable. The product must be filtered or centrifuged free of the salt and must then be washed with solvents which, in turn, must be removed by distillation. In spite of washing, large losses of yield result from adsorption onto the salt and the salt wastes have to be disposed of.